How to start imported Alembic animation at a specific frame
Related

looping alembic
reverse alembic



Once you imported an Alembic Cache, the object in Blender will have an Alembic Cache Constraint.


Check Override Frame.

Go to your desired starting frame. Type 1 in the Frame property. Hover over the property and press I to set a key. Set a key on the next frame with the value of 2. In the Graph Editor, press ShiftE and select Linear Extrapolation. Then select the first keyframe, press T and make it a constant key.


Using a python expression
Type the following expression in the frame property:
#(1 - round((frame - frame_offset)%0.99999)) * (frame - frame_offset) + frame_hold

Replace frame_offset with the desired starting frame. Replace frame_hold with the frame which is held before the starting frame. frame doesn't change, it is a python variable holding the current frame number.
Example. To achieve the following:
Frame     Calculated
11        2   |
12        2   |  The frame held before is no 2.
13        2   |
14        2   |
15        2   &lt; This is the starting frame (15).
16        3
17        4
18        5
19        6
20        7

The expression would be:
#(1 - round((frame - 15)%0.99999)) * (frame - 15) + 2